well... keep in mind the old adage that a happy customer probably will tell noone but an unhappy customer is sure to tell everyone.
you are asking a lot of questions for which there is probably no answer. it'd be like me asking the same bout a commodore - some people love 'em and some people never will and i reckon i'd never get a decent answer.
and what about the s300 capacity for moving logs? are you asking is it better or what?
i suggest you try using your search engine and see what you find bout the s250 herein, i'm sure there will be plenty. and then come back and ask your pointed questions...
the 250 and 300 share the same engine, the 330 uses a larger engine afaik, i like my 330, it is a good toy with a decent sized bucket on it.
the 250 and 300 are the same machine essentially except for a few counterwieghts.
tick the hiflow box if it is a reasnable option, it is handy if you choose to run the stump grinder for example. the bobcat stump grinder works very nicely if you give it a bit of flow.
as for kubotas, a reasonable brand of engine imho. i've seen the blighters beating away in boats long long past their use by date.